Chuck jaw changer for a machine tool

ABSTRACT

A chuck jaw changer is disclosed as mounted on the headstock (24) of an N/C lathe (22) for automatically changing the set of gripping jaws (32) of a quick change chuck (28) on a work spindle (26) with any of other interchangeable sets of gripping jaws (32&#39;) being held by a rotary, indexing jaw magazine (34). The jaw magazine has formed therein several jaw grooves (150) each for holding one set of gripping jaws (32&#39;), or the jaw set (32) withdrawn from the chuck, slidably engaged therein in a row. An indexing mechanism (35) revolves the jaw magazine relative to the machine tool for bringing any of the jaw grooves into line with that one of radial jaw guideways (54) of the chuck which is being held in a prescribed jaw change position on the work spindle. A jaw transfer mechanism (36) operates for successively transferring the set of jaws from the chuck into an empty jaw groove in the jaw magazine, and a different set of jaws from the jaw magazine to the chuck. Thus the transfer of each set of gripping jaws from the chuck to the jaw magazine or vice versa can be completed while the magazine is held at a standstill on the machine tool.

BACKGROUND OF THE INVENTION

This invention relates to machine tools in general and, in particular,to lathes or like machines having a chuck with adjustable gripping jawsfor holding work to be operated upon. The invention is directed morespecifically to a chuck jaw changer for use with such a machine tool forautomatically changing the gripping jaws of the chuck as required by thevarying sizes of work to be held thereby.

With the advent and dissemination of the numerical control (N/C or NC)technique, the metalworking industry has concentrated research anddevelopment efforts on the automation of all phases of machine toolingfor higher production and less human labor. The change of chuck jaws isno exception. A variety of devices have been suggested, with someaccepted commercially, for autmatically changing the sets of grippingjaws of chucks on lathes and other classes of machine tools. These priorart devices are subject to the objection, however, that the number ofinterchangeable sets of jaws is rather limited in comparison with thesize of the device. A chuck jaw changer for installation on a machinetool should be as compact as possible to avoid interference with theoperation of the machine tool itself. Contrary to this requirement isthe current demand for a greater number of interchangeable sets of jaws.Another demand currently imposed by the metalworking industry on chuckjaw changers is the reduction of the period of time required for achange from one set of jaws to another.

SUMMARY OF THE INVENTION

The present invention provides a novel chuck jaw changer which makespossible a quicker change from one set of gripping jaws to another thanheretofore and which can hold in stock any required number ofinterchangeable jaw sets without the possibility of interference withthe operation of the machine tool for use therewith.

The chuck jaw changer in accordance with the invention may be broadlysummarized as comprising a chuck having a chuck body to be mounted onthe work spindle of a machine tool, with a set of gripping jawsremovably engaged in respective radial jaw guideways in the chuck body.Each gripping jaw is to be slid into and out of one jaw guideway whenthat guideway is held in a prescribed first jaw change position on thework spindle. Movably mounted on the machine tool is an indexing jawmagazine having jaw grooves each for holding an additional set ofgripping jaws, or the first recited set of gripping jaws on beingwithdrawn from the chuck body, slidably engaged therein in a row. Thejaw magazine is provided with an indexing mechanism thereby to be movedrelative to the machine tool so as to bring any of the jaw grooves, withor without a set of gripping jaws engaged therein, to a preassignedsecond jaw change position where that jaw groove is in line with thatone of the jaw guideways in the chuck body which is in the first jawchange position. The jaw magazine is so adapted that the alignedgripping jaws in the first and second jaw change positions are held atconstant pitch distances. Further included is a jaw transfer mechanismreciprocably movable between the chuck and the jaw magazine a distanceequal to the pitch distance between the gripping jaws aligned in thefirst and second jaw change positions. The jaw transfer mechanism cansimultaneously engage the set of gripping jaws being held in the jawgroove in the second jaw change position for transferring the same, bythe repetition of the reciprocating movement between chuck and jawmagazine, into the successive jaw guideways that are brought to thefirst jaw change position. Further the jaw transfer mechanism can engagethe gripping jaw in the jaw guideway being held in the first jaw changeposition for transferring the same into the empty jaw groove being heldin the second jaw change position.

It is to be appreciated that each jaw groove in the jaw magazine holds acomplete set of gripping jaws, which can be successively transferredinto the separate jaw guideways in the chuck body as these guideways aremoved to the first jaw change position one after another by the stepwiserotation of the work spindle of the machine tool. The jaws in the chuckbody guideways can also be successively carried into an empty jaw groovein the jaw magazine being held in the second jaw change position. Eachset of gripping jaws can thus be transferred from chuck body to jawmagazine, or vice versa, while the latter is standing still on themachine tool. This greatly shortens the jaw change time in comparisonwith the case where the jaw magazine holds one jaw in each groove and somust be indexed for each jaw to be transferred to or from the chuckbody.

The mounting of each set of jaws in one jaw groove in the jaw magazineyields another advantage that the magazine can be installed on a smallerarea on the machine tool than if each jaw groove holds one jaw. Thenumber of interchangeable sets of jaws may therefore be increased asrequired without the possibility of bringing about inconveniences to themachine tool operation.

The jaw transfer mechanism is also well calculated for the simplicity ofconstruction. It linearly travels back and forth a distance equal to thepitch of the jaws aligned in the first and second jaw change positions,for successive jaw transfer between chuck and magazine. Thus a simplelinear actuator such as a fluid actuated cylinder may be employed forsuch travel of the jaw transfer mechanism over the variable distance.

In a preferred embodiment the jaw magazine takes the form of anupstanding cylinder, with the jaw grooves defined in its periphery so asto extend parallel to its axis at constant circumferential spacings.Both indexing mechanism and jaw transfer mechanism can be advantageouslyhoused within the cylindrical jaw magazine for the provision of acompact chuck jaw changer.

It is also recommended that, notwithstanding the compactness of theapparatus, the jaw magazine together with the indexing mechanism and thejaw transfer mechanism housed therein be made retractable on the machinetool, as in the embodiment disclosed herein. The jaw magazine, theindexing mechanism, the jaw transfer mechanism, and other partshereinafter set forth constitute in combination what is herein termed ajaw change assembly. Held retracted away from the chuck during the usualoperation of the machine tool, the jaw change assembly will present noimpediment at all to the machine tool operation and will further be freefrom the attack of the chips or cutting oil.

The above and other features and advantages of the present invention andthe manner of realizing them will become more apparent, and theinvention itself will best be understood, from a study of the followingdescription and appended claims, with reference had to the attacheddrawings showing a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical section through the chuck jaw changer constructedin accordance with the principles of the present invention and asmounted in position on a lathe, the view showing the jaw change assemblyin retracted position;

FIG. 2 is a view similar to FIG. 1 except that the jaw change assemblyis shown in a working position for jaw change;

FIG. 3 is a top plan of the complete apparatus, depicting the retractedposition of the jaw change assembly by the solid lines and the workingposition thereof by phantom outlines;

FIG. 4 is an elevation of the complete apparatus as seen from the righthand side of FIG. 1;

FIG. 5 is an enlarged, fragmentary axial section through the quickchange chuck mounted in position on the lathe of FIG. 1 for use with orin the chuck jaw changer of this invention;

FIG. 6 is a section taken along the line VI--VI in FIG. 1 and showing inparticular the jaw magazine together with the magazine indexingmechanism, jaw transfer mechanism, and retractable retainer assemblydisposed internally of the jaw magazine;

FIG. 7 is an enlarged, fragmentary vertical section through the jawchange assembly, showing in particular the magazine indexing mechanism,jaw transfer mechanism, and unlocking mechanism which are all built intothe jaw magazine;

FIG. 8 is a fragmentary vertical section through the jaw magazine,showing in particular the retractable retainer assembly seen also inFIG. 6;

FIG. 9 is a section taken along the line IX--IX in FIG. 2 and showing inparticular the unlocking mechanism together with those parts of thechuck which are associated with the unlocking mechanism;

FIG. 10 is a fragmentary vertical section through the chuck jaw changerof FIG. 1, shown in a step in its operation;

FIG. 11 is an enlarged, fragmentary vertical section through the chuckjaw changer, shown in another step in its operation; and

FIGS. 12 and 13 are views similar to FIG. 10 but showing the chuck jawchanger in further different steps in its operation.

DETAILED DESCRIPTION OF THE INVENTION General

The chuck jaw changer in accordance with the invention is generallylabeled 20 is FIGS. 1 through 4 and therein shown as structured for usewith an N/C lathe 22 as an example of machine tool to which theinvention finds application. Inasmuch as the N/C lathe 22 is familiar tothe machine tool specialists, only its headstock 24 and work spindle 26projecting forwardly (rightwardly as viewed in FIGS. 1 through 3)therefrom are shown for simplicity.

Conventionally mounted on the work spindle 26 of the N/C lathe 22 is aquick change chuck 28 which may be considered a part of the chuck jawchanger 20 for the purposes of the invention. The chuck 28 comprises achuck body 30 rigidly attached to the work spindle 26, and a set ofgripping jaws 32 replaceably mounted on the chuck body and normallylocked against displacement relative to the same. The jaw changer 20automatically changes the jaw set 32 on the chuck body 30 with any ofseveral other different sets of gripping jaws 32' held in stock thereby.

With reference further to FIGS. 1 through 4 the exemplified chuck jawchanger 20 additionally comprises:

1. a rotary, indexing jaw magazine 34 operatively mounted on theheadstrock 24 of the lathe 22 and releasably holding the additional setsof gripping jaws 32' at constant circumferential spacings thereon;

2. a magazine indexing mechanism 35 for incrementally revolving the jawmagazine 34 relative to the lathe 22 so as to bring any desired one ofthe gripping jaw sets 32' into alignment with the chuck 28 for jawchange;

3. a jaw transfer mechanism 36 for transferring the sets of grippingjaws 32 and 32' between chuck body 30 and jaw magazine 34;

4. a retractable retainer assembly 38 closely associated with the jawtransfer mechanism 36 for temporarily holding the gripping jaws 32 and32' on the jaw magazine 34 during their transfer to or from the chuckbody 30;

5. an unlocking mechanism 40 for unlocking the gripping jaws 32 from thechuck body 30 preparatory to their transfer to the jaw magazine 34; and

6. A jaw guide 42 for guiding the gripping jaws 32 and 32' beingtransferred by the transfer mechanism 36 between chuck body 30 and jawmagazine 34.

The above listed components 34, 35, 36, 38, 40 and 42 all constituteparts of a jaw change assembly 44 mounted on the headstock 24 of thelathe 22 for movement between a retracted position of FIG. 1 and aworking position of FIG. 2. The jaw change assembly 44 stays in theretracted position during the usual machining operation of the lathe 22.When moved to the working station, then, the jaw change assembly 44operates to change the jaw set 32 on the chuck body 30 with any desiredone of the other jaws sets 32' on the jaw magazine 34. Provided for suchmovement of the jaw change assembly 44 between the working and retractedpositions on the lathe 22 are:

1. a longitudinal transport mechanism 46, FIGS. 3 and 4, forreciprocably moving the jaw change assembly 44 longitudinally of thework spindle 26 of the lathe 22; and

2. a radial transport mechanism 48, FIGS. 1 and 2, for reciprocablymoving the jaw change assembly 44 radially of the work spindle 26 or ofthe chuck 28 thereon.

In the illustrated embodiment the radial transport mechanism 48 movesthe jaw change assembly 44 vertically. The word "radial" is used becausethe jaw change assembly 44 may not necessarily travel vertically, butonly radially of the work spindle 26, depending upon the angularposition of the chuck jaw changer 20 on the machine tool about the axisof the work spindle. The longitudinal transport mechanism 46 moves thejaw change assembly 44 between a rear position of FIG. 1, away from thechuck 28, and a front position of FIG. 2, closer to the chuck. Theradial transport mechanism 48 moves the jaw change assembly 44 betweenan upper position of FIG. 1, radially outward of the chuck 28, and alower position of FIG. 2, radially inward of the chuck. The jaw changeassembly 44 is in the retracted position when held in the rear positionby the longitudinal transport mechanism 46 and in the upper position bythe radial transport mechanism 48. In its working position, on the otherhand, the jaw change assembly 44 is held in the front position by thelongitudinal transport mechanism 46 and in the lower position by theradial transport mechanism 48.

Given hereafter is a more extensive discussion of the above listedcomponents of the chuck jaw changer 20, which for convenience wll bedivided under several headings, followed by the operational descriptionof the complete apparatus. The listed components will be discussed inthe following order:

1. Quick change chuck 28.

2. Longitudinal transport mechanism 46.

3. Radial transport mechanism 48.

4. Jaw magazine 34.

5. Magazine indexing mechanism 35.

6. Jaw transfer mechanism 36.

7. Retractable retainer assembly 38.

8. Unlocking mechanism 40.

9. Jaw guide 42.

Quick Change Chuck

Although the lathe chuck 28 is shown sectioned in FIGS. 1 and 2, FIG. 5better illustrates its construction on an enlarged scale. As will beseen also from its front view given in FIG. 4, the particular chuckadopted here is of the type known as the three jaw universal chuck,having the three gripping jaws 32 jointly moved in and out by a wedgingaction. It is to be understood, however, that other types of chuckscould be employed within the scope of this invention.

Mounted on the work spindle 26 for simultaneous rotation therewith, thechuck body 30 has three radial guideways 50 formed therein at constantangular spacings about the axis of the work spindle 26. Each guideway 50slidably receives a slide 52. Another set of three radial guideways 54are defined in the chuck body 30 for slidably receiving the T sectionedshoe portions 56 of the respective gripping jaws 32. These shoe portionsare opposed to the respective slides 52 within the chuck body 30.

A locking mechanism 58 locks each gripping jaw 32 against radialdisplacement relative to the opposed one of the slides 52 and, inconsequence, to the chuck body 30. Each locking mechanism 58 comprises aprimary detent 60 mounted in each slide 52 for sliding motion toward andaway from the shoe portion 56 of the opposed gripping jaw 32 in adirection parallel to the work spindle 26. The primary detent 60 has aseries of teeth 62 cut in its front face for positive engagement with aseries of complementary teeth 64 on the opposed surface of the grippingjaw shoe portion 56. A secondary detent 66 is mounted in each primarydetent 60 for sliding motion in a direction parallel to the work spindle26. This secondary detent also has a tooth 68 on its front face forpositive engagement with the teeth 64 on the gripping jaw shoe portion56. A key 70 is embedded radially in the primary detent 60 into relativesliding engagement in a longitudinal keyway 72 in the secondary detent66 for preventing its detachment from the primary detent while allowingits longitudinal movement relative to the primary detent within limits.Compression springs 74, one seen, act between slide 52 and primarydetent 60 to urge the latter into positive engagement with the grippingjaw shoe portion 56. Another compression spring 76 acts between slide 52and secondary detent 66 to urge the latter also into positive engagementwith the gripping jaw shoe portion 56.

Thus, as long as the primary detent 60 is sprung into toothed engagementwith the gripping jaw shoe portion 56, the locking mechanism 58 remainsin effect to lock the gripping jaw 32 onto the opposed slide 52. Whenthus locked onto the slide 52, the gripping jaw 32 moves therewith alongone of the jaw guideways 54 relative to the chuck body 30. The secondarydetent 66 functions to yieldably hold the gripping jaw 32 on the chuckbody 30 upon disengagement of the primary detent 60 from the jaw, aswill be explained later in more detail.

Provided for the desired radial motion of the gripping jaws 32 with theslides 52, as for chucking and unchucking work, is a wedge member 78mounted centrally in the chuck body 30 for sliding movement in its axialdirection. The wedge member 78 has a plurality of, three in thisembodiment, undercut grooves 80 extending at an angle to the axis of thechuck. Each slide 52 has a T sectioned wedge portion 82 slidably engagedin one angled undercut groove 80 in the wedge member 78. The wedgemember 78 is fastened at 84 to a conventional actuating mechanismcomprising a rotary actuator 86, FIG. 1, thereby to be moved back andforth axially of the chuck 28. The bidirectional axial movement of thewedge member 78 results, of course, in the radially inward or outwardmovement of the slides 52 and therefore of the gripping jaws 32 alongthe radial jaw guideways 54.

The gripping jaws 32 must be unlocked from the slides 52 and withdrawnout of the jaw guideways 54 in the chuck body 30 for a change with someother set of gripping jaws 32' on the jaw magazine 34. Toward this endan unlocking pin 88 is slidably mounted in each slide 52. Movableradially of the chuck, the unlocking pin 88 has an inclined surface forsliding engagement with a correspondingly inclined surface of theprimary detent 60. The contacting inclined surfaces of the primarydetent 60 and unlocking pin 88 are such that upon forced depression ofthe unlocking pin into the slide 52, the primary detent travelsrearwardly against the bias of the compression springs 74 out ofengagement with the associated gripping jaw shoe portion 56, therebyunlocking the gripping jaw from the slide. The unlocking pin 88 uponforced depression into the slide 52 partly enters a recess 90 in thewedge member 78. When thrusted forwardly, the wedge member 78 pushes theunlocking pin 88 out of the recess 90, allowing the primary detent 60 tobe sprung back into positive engagement with the gripping jaw shoeportion 56.

Disengaged from the primary detent 60 by the depression of the unlockingpin 88 as above, the gripping jaw 32 is still held in position on thechuck body 30 by the secondary detent 66, the latter being held inengagement with the gripping jaw under the relatively light force of thecompression spring 76. However, the gripping jaw 32 is movable radiallyof the chuck body 30 against the force of the compression spring 76 uponapplication of an external force as by the jaw transfer mechanism 36.

The quick change chuck 28 of the foregoing construction rotates with thework spindle 26 under the control of the numerical control system or"director", not shown, of the N/C lathe 22. The "director" stops therotation of the chuck 28 in predetermined angular positions where one ofthe radial jaw guideways 54 in the chuck body 20 is in what is hereincalled a jaw change position, designated A in FIGS. 1, 2 and 4. Jawtransfer between chuck 28 and jaw magazine 34 is to be effected whileeach jaw guideway 54 is in this jaw change position A. In theillustrated embodiment the jaw change position A of each jaw guideway 54is vertically upward of the chuck axis since the jaw change assembly 44is mounted on the top of the headstock 24 of the lathe 22. It willtherefore be apparent that the jaw change position of the jaw guideways54 may be in any other direction about the chuck axis depending upon theangular position of the jaw change assembly 44 on the machine tool aboutthe chuck axis.

Longitudinal Transport Mechanism

Reference is directed to FIGS. 1, 3 and 4 for a description of thelongitudinal transport mechanism 46 reciprocably moving the jaw changeassembly 44 longitudinally of the work spindle 26. Included is acarriage 92 carrying the jaw change assembly 44 via the radial transportmechanism 48. The carriage 92 is slidably mounted on the headstock 24for linear reciprocation along guide means 94 between the rear positionof FIG. 1 and the front position of FIG. 2. Rigidly mounted on theheadstock 24, a fluid actuated, double acting cylinder 96 has a pistonrod 98 coupled to the carriage 92 via an L-shaped member 100 to causesuch travel thereof. This cylinder will be referred to as thelongitudinal cylinder hereafter by way of distinction from othercylinders to be set forth subsequently.

A stud bolt 102 is rigidly anchored at one end of the L-shaped member100 on the carriage 92 and extends parallel to the longitudinal cylinder96. A flange 104 on the rod end of the longitudinal cylinder 96 has abore 106 to allow the stud bolt 102 to extend slidably therethrough. Apair of stop nuts 108 and 110 are threadedly mounted on the stud bolt102, in the vicinities of its opposite ends, and are locked againstaxial displacement. Accordingly, with the extension and contraction ofthe longitudinal cylinder 96, its flange 104 moves into abutment againstthe stop nuts 108 and 110 to stop the carriage 92 in the exact front andrear positions.

Radial Transport Mechanism

A study of FIG. 1 will make clear the construction of the radialtransport mechanism 48 which moves the jaw change assembly 44 up anddown on the carriage 92. The radial transport mechanism includes anupstanding, hollow column 112 mounted on the carriage 92 and securedthereto as by screws 114. The axis of this hollow column 112 crosses theaxis of the work spindle 26, or of the chuck 28 thereon, at rightangles. The hollow column 112 has a fluid actuated, double actingcylinder 116, hereinafter referred to as the radial cylinder, threadedlyand coaxially engaged at 118 in its top end. The piston rod 120 of theradial cylinder 116 extends upwardly therefrom.

Slidably fitted over the column 112 on the carriage 92 is a hollowmagazine spindle 122 which is movable up and down with the jaw changeassembly 44 but which is restrained from angular displacement relativeto the column 112. The magazine spindle 122 has a sot 124 definedlongitudinally therein for slidably receiving a key 126 protrudinglaterally from the column 112. The key 126 allows the up and down motionof the magazine spindle 122 but prevents its rotation relative to thecolumn 112.

The piston rod 120 of the radial cylinder 116 has a threaded upwardextension 128 of reduced diameter extending through a cap 130 andprojecting upwardly therefrom. A locknut 132 is fitted over thisprojecting end of the piston rod extension 128 to hold the cap 130 fastagainst the piston rod 120. The cap 130 is threadedly engaged in atubular, flanged retainer 134 which is itself threadedly engaged in thetop end of the hollow magazine spindle 122.

It is now apparent that the magazine spindle 122 travels up and downwith the extension and contraction of the radial cylinder 116. The jawmagazine 34 is rotatably mounted on this magazine spindle 122 whereasthe other components of the jaw change assembly 44, such as the magazineindexing mechanism 35 and jaw transfer mechanism 36, are nonrotatablymounted thereon. With the extension and contraction of the radialcylinder 116, therefore, the complete jaw change assembly 44 movesbetween the upper position of FIG. 1 and the lower position of FIG. 2.How the magazine 122 supports the listed components of the jaw changeassembly 44 will become apparent as the description progresses.

Jaw Magazine

The rotary, indexing jaw magazine 34 appears in all of FIGS. 1 through 4and also in FIG. 6, the latter figure showing the jaw magazine in ahorizontal section taken along the line VI--VI of FIG. 1. Theconstruction of the jaw magazine 34 will be understood from aconsideration of only FIGS. 1, 4 and 6. It will be observed from thesefigures that the jaw magazine 34 takes the form of an upstanding, hollowcylinder or drum 136 concentric with the magazine spindle 122 andtherefore with the column 112. The cylindrical jaw magazine has a top138 and a bottom 140 closing its opposite ends. The magazine top 138 andbottom 140 have bores 142 and 144 defined centrally therethrough torotatably receive the hollow magazine spindle 122 as in FIG. 1. Themagazine bottom 140 bears against a flange 146 on the bottom end of themagazine spindle 122 via a thrust beaing 148. The tubular flangedretainer 134, set forth in connection with the radial transportmechanism 48, has its flange slidably held against the magazine top 138to prevent the upward displacement of the jaw magazine relative to themagazine spindle 122 which is moved up and down by the radial cylinder116. Accordingly the jaw magazine 34 is both rotatable and movablevertically with respect to the carriage 92.

As best seen in FIGS. 4 and 6, the jaw magazine 34 has a plurality of,fifteen in the illustrated embodiment, undercut jaw grooves 150 definedtherein so as to extend parallel to its axis at constant circumferentialspacings and throughout the axial dimension of the jaw magazine. Eachjaw groove 150 slidably receives the shoe portions 56' of one set ofgripping jaws 32', or the shoe portions 56 of the set of gripping jaws32 now shown mounted on the chuck body 30. The length of each jaw groove150 must be sufficient to hold one set of gripping jaws in alignment.

The exemplified quick change chuck 28 is of three jaw construction, andthe exemplified jaw changer 20 is intended to allow the chuck to makeinterchangeable use of fifteen sets of gripping jaws 32 and 32'. Thusthe jaw magazine 34 holds forty-five gripping jaws at the maximum.

The jaw magazine 34 is to be revolved by the indexing mechanism 35 tobring any of its jaw grooves 150 into line with that one of the jawguideways 54 in the chuck body 30 which is in the jaw change position A,when the complete jaw change assembly 44 is in the working position asin FIG. 2. This particular angular position of each jaw guideway 54 ishereinafter referred to as the second jaw change position incontradistinction from the first recited jaw change position A of thejaw guideways in the chuck body. The second jaw change position isindicated at B in FIGS. 4 and 6. Jaw change between a jaw guideway inthe chuck body and a jaw groove in the jaw magazine is to be effectedwith that jaw guideway held in the first jaw change position, with thatjaw groove in the second jaw change position, and of course with the jawchange assembly in the working position.

FIG. 1 reveals a set of two annular recesses 152 and 154 and another setof three annular recesses 156, 158 and 160 cut in the inside surface ofthe jaw magazine 34 at vertical or axial spacings so as to cross the jawgrooves 150 at right angles. The first set of annular recesses 152 and154 are disposed at the lower ends of the shoe portions 56' (or 56) ofthe topmost and middle rows of gripping jaws 32' (or 32) on the jawmagazine 34. The second set of annular recesses 156, 158 and 160 aredisposed on a level with notches 162 in the shoe portions 56' (or 56) ofthe three rows of gripping jaws 32' (or 32) on the jaw magazine 34. Thereasons for the provision of this secnd set of recesses will becomeapparent from the subsequent description of the jaw transfer mechanism36 and retractable retainer assembly 38.

The first set of recesses 152 and 154 receive with clearance annular jawrests 164 and 166 respectively. Another annular jaw rest 168 is disposedjust below the jaw magazine 134. Arranged concentrically with the jawmagazine 34 and nonrotatably supported by means hereinafter set forth,the three annular jaw rests 164, 166 and 168 hold thereon the sets ofgripping jaws 32' (and 32) engaged in the jaw grooves 150 by makingrelatively sliding contact with the bottom ends of their shoe portions56' (and 56). The gripping jaws are to slide over the jaw rests 164, 166and 168 with the rotation of the jaw magazine 34. As indicated at 170 inFIG. 6, all these jaw rests are cut off in the second jaw changeposition B of the jaw grooves 150 for the passage of the gripping jaws32' being transferred to the chuck body 30, or of the gripping jaws 32being transferred from the chuck body. In this second jaw changeposition the retractable retainer assembly 38 functions to temporarilysupport the gripping jaws 32' to be transferred to the chuck body 30, aswell as the gripping jaws 32 transferred from the chuck body, therebypreventing them from falling through the breaks 170 in the jaw rests164, 166 and 168.

FIGS. 1 and 6 also illustrate the means for supporting the three jawrests 164, 166 and 168. The upper two jaw rests 164 and 166 are eachaffixed as by screws 172 to the distal ends of a plurality of supportarms 174 proximally anchored to a mounting sleeve 176 which is fittedover the hollow magazine spindle 122. The mounting sleeve 176 is lockedagainst rotation relative to the magazine spindle 122 by two keys 178and against axial displacement by a locknut 180. Consequently themounting sleeve 176 with the upper two jaw rests 164 and 166 isnonrotatable but is movable up and down with the jaw magazine 34. Thelowermost jaw rest 168 is bracketed at 181 to the bottom flange 146 ofthe magazine spindle 122, so that the lowermost jaw rest is in fixedrelation to the upper two jaw rests 164 and 166.

The vertical positions of the three jaw rests 164, 166 and 168 must beso determined in relation to one another and to the chuck 28 that, whenthe jaw change assembly 44 is in the working position as in FIG. 2, theset of gripping jaws 32' in the second jaw change position B and thegripping jaw 32 in the first jaw change position A may be held atconstant pitch distances P, as indicated in FIG. 2. The pitch distance Pshould be a minimum required for holding each set of gripping jaws 32'on the jaw magazine 34 without mutual interference, in order to minimizethe axial dimension of the jaw magazine. However, since the chuck 28lies some distance below the top of the carriage 92 on the latheheadstock 24, the pitch distance between the gripping jaw 32 in thefirst jaw change position A and the lowermost gripping jaw 32' in thesecond jaw change position B cannot possibly be reduced indifinitely,for, should this pitch distance be made too small by lowering theposition of the lowermost jaw rest 168, the carriage 92 would interferewith the gripping jaws 32' on this lowermost jaw rest.

The only practical solution to the above problem is the sloping of thelowermost jaw rest 168. As indicated at 182 in FIG. 1, the top edge ofthe lowermost jaw rest 168 slopes downwardly as it extends toward itsopposite extremities bounding the part where it is cut off, as at 170 inFIG. 6, in the second jaw change position B. This makes it possible toposition each gripping jaw on the lowermost jaw rest 168 sufficientlyclose to the chuck 28 without the possibility of the jaw hitting thecarriage 92 while being revolved with the jaw magazine 34.

The jaw magazine 34 is further provided with means designed tofacilitate the manual engagement of the gripping jaws 32' into and outof engagement in the jaw grooves 150. Three such means are provided forthe respective jaw rests 164, 166 and 168. Since the three means can allbe identical in construction, only those for the topmost jaw rest 164are illustrated in FIG. 6 and generally designated 184. Therepresentative means 184 include a retractable bridge 186 fitted in adiscontinuity 188 in the jaw rest 164 for movement in its radialdirection. The position of the discontinuity 188 in the jaw rest 164could be anywhere opposite one of the jaw grooves 150 in the jawmagazine 34, except the second jaw change position B. Normally theretractable bridge 186 slightly intrudes into the opposed jaw groove 150and has its top edge flush with the top edge of the jaw rest 164. Aslong as being held in the illustrated normal position, the retractablebridge 186 allows one gripping jaw 32' to rest thereon, or the topmostrow of gripping jaws 32' to slide thereover, just as if the jaw rest 164had no such discontinuity.

Projecting radially inwardly from the retractable bridge 186 are a pairof bosses 190 slidably extending through respective openings 192 in aguide 194 formed integral with, and between, the two neighboring ones ofthe radial support arms 174 holding the jaw rest 164. A pair of stems196 further extend radially inwardly from the respective bosses 190 andslidably engaged in bores 198 in another guide 200 also formed integralwith, and between, the two neighboring ones of the support arms 174.Surrounding each stem 196, a compression spring 202 acts between bridge186 and guide 200 to bias the former radially outwardly of the jaw rest164. A head 204 on each stem 196 abuts against the guide 200 to limitthe radially outward motion of the bridge 186 and to normally hold thesame in the illustrated position.

The retractable bridge 186 may therefore be pressed radially inwardlyagainst the forces of the compression springs 202 for mounting agripping jaw 32' in the jaw grooves 150. The bridge will spring backwhen subsequently released from the pressure, allowing the gripping jaw32' to rest thereon. While holding the shoe portion of any gripping jawthereon, the retractable bridge 186 has its lower end portion projectingbeyond the bottom of the gripping jaw. For dismounting the gripping jaw,therefore, this projecting lower end portion of the bridge is manuallypressed inwardly to move the bridge out of engagement with the jaw.

Magazine Indexing Mechanism

Reference may be had to FIGS. 6 and 7 for the details of the indexingmechanism 35 for the jaw magazine 34 although it is shown also in FIGS.1 and 2. The magazine indexing mechanism 35 includes an indexing motor210 for intermittently driving the jaw magazine 34 by means of a Genevamovement set forth hereafter. The indexing motor 210 is mounted on abracket 212 secured to the mounting sleeve 176 around the hollowmagazine spindle 122. The output shaft 214 of the indexing motor 210 hasa rotor 216 keyed thereto at 218. The rotor 216 carries on its undersidea pair of drive cams or pins 220 in positions of symmetry with respectto the axis of the motor output shaft 214. The drive cams 220 aremovable into and out of engagement in a series of slots 222 cut in theperiphery of a Geneva wheel 224 which is rotatably fitted over themounting sleeve 122 and which is screwed at 226 to the bottom 140 of thejaw magazine 34 for joint rotation therewith. The slots 222 of theGeneva wheel 224 are arranged at constant angular spacings, with theirangular positions corresponding to those of the jaw grooves 150 in thejaw magazine 34.

Thus, upon rotation of the motor output shaft 214 through an angle of180 degrees in either direction from its FIG. 6 position, one of thedrive cams 220 becomes engaged in one of the slots 222 in the Genevawheel 224 and turns the same through a unit angle. The unit angle ofrotation of the Geneva wheel 224, and therefore of the jaw magazine 34,is twenty four degrees in the present embodiment as the jaw magazine hasfifteen jaw grooves 150 as aforesaid. Any of the jaw grooves 150 canthus be exactly placed in the second jaw change position B.

At 228 in FIG. 7 is shown a proximity switch, affixed to the magazinespindle 122 via a bracket 230, for terminating the rotation of theindexing motor 210 when any desired jaw groove 150 in the jaw magazine34 reaches the second jaw change position. The promity switch 228 is tobe activated by an annular row of idler rods (to be explained presently)which are associated with the respective jaw grooves 150 and whichrotate with the jaw magazine 34.

The indexing motor 210 is also under the control of a jaw identifyingswitch assembly seen at 232 in FIG. 1. Bracketed at 234 to the mountingsleeve 176, the switch assembly 232 has four vertically spaced apartfeeler arms 236 projecting therefrom in a radially outward direction ofthe jaw magazine 34. Arranged on the opposed inside surface portion ofthe jaw magazine 34 to selectively activate the feeler arms 236 are aset of switch actuators 238 characteristically associated with each jawgroove 150. The switch assembly 232 identifies each jaw groove from thenumber and vertical positions of the associated set of switch actuators238.

Jaw Transfer Mechanism

With reference to FIGS. 1, 4, 6 and 7 the jaw transfer mechanism 36 iswholly disposed within the jaw magazine 34, in the immediate vicinity ofthe second jaw change position B, for the transfer of the gripping jaws32 from chuck body 30 to jaw magazine 34, and of the gripping jaws 32'from jaw magazine to chuck body.

The jaw transfer mechanism 36 includes a fluid actuated, double acting,double ended rod cylinder 240 (hereinafter referred to as the transfercylinder) generally extending parallel to the magazine spindle 122. Thetransfer cylinder 240 has a piston rod 242 extending downwardlytherefrom and rigidly anchored to a bracket 244 on the mounting sleeve176. Another piston rod 246 of the transfer cylinder 240, extendingupwardly therefrom, is likewise anchored to another bracket 248 on themounting sleeve 176. With its two piston rods 242 and 246 both rigidlysupported by the mounting sleeve 176, the transfer cylinder 240 has onlyits cylinder body 250 moved up and down with the pressurization of itspair of opposed fluid chambers. The stroke of the transfer cylinder 240is set equal to the pitch P, FIG. 2, of the gripping jaws 32 and 32'aligned in the first and second jaw change positions A and B.

The transfer cylinder 240 has a pair of support arms 252 projectinglaterally therefrom. These support arms firmly support a sleeve bearing254 in which there is rotatably received a reduced diameter journalportion 256 of a transfer rod 258 extending vertically along that one ofthe jaw grooves 150 in the jaw magazine 34 which is in the second jawchange position B. A locknut 260 locks the transfer rod 258 againstaxial displacement relative to the sleeve bearing 254. It is thereforeapparent that the transfer rod 258 is both rotatable bidirectionallyabout its own axis and movable up and down with the transfer cylinder240, with respect to the jaw magazine 34.

The transfer rod 258 has three protuberances 262, 264 and 266 formed invertically and constantly spaced apart positions thereon and projectinglaterally therefrom in the same direction. When the transfer rod 258 isheld raised by the transfer cylinder 240 as in FIG. 1, its protuberances262, 264 and 266 are on the same levels respectively with the notches162 in the shoe portions 56' of the three gripping jaws 32' aligned inthe second jaw change position B. The transfer rod protuberances 262,264 and 266 are movable into engagement in the notches 162 of the threegripping jaws 36' as the transfer rod 258 is revolved by means set forthsubsequently, for transferring them down to the chuck body 30 one afterthe other by the subsequent longitudinal reciprocation of the transferrod. Further, when the transfer rod 258 is lowered by the transfercylinder 240, the lowermost protuberance 266 thereon is engageable inthe notch 162 of that gripping jaw 32 on the chuck body 30 which isbeing held in the first jaw change position A, for carrying the jaw upto the jaw magazine 34.

The topmost protuberance 262 on the transfer rod 258 is formed on itsjournal portion 256 received in the sleeve bearing 254. Thus the sleevebearing 254 has formed therein a slot 268 to allow the topmostprotuberance 262 to project outwardly therethrough and, with thebidirectional rotation of the transfer rod 258, to turn through an anglerequired for moving into and out of engagement in the notch 162 of thetopmost gripping jaw 32' in the second jaw change position B.

The following means are provided for the bidirectional rotation of thetransfer rod 258 about its own axis. As best seen in FIG. 7, theaforesaid bracket 244 on the mounting sleeve 176 has a cam rod 270mounted thereto for longitudinal sliding motion in a direction parallelto the transfer rod 258. The cam rod 270 has a larger diameter portion272 and a smaller diameter portion 274, with a shoulder 276therebetween. A key 278 on the bracket 244 is slidably engaged in akeyway 280 in the larger diameter portion 272 of the cam rod 270 toprevent its angular displacement. A compression spring 282 around thesmaller diameter portion 274 of the cam rod 270 biases the same upwardlyof the bracket 244 and normally holds the cam rod in the illustratedposition with its shoulder 276 butting on the bracket. The largerdiameter portion 272 of the cam rod 270 has a cam groove 284 formedtherein.

The bracket 244 is recessed at 286 to accommodate a sector gear 288which is rotatably fitted over the larger diameter portion 272 of thecam rod 270. The sector gear 288 is rotatable relative to the bracket244 but is thereby prevented from axial displacement relative to thesame. Embedded in the sector gear 288, a cam follower pin 290 isslidably engaged in the cam groove 284 in the larger diameter portion272 of the cam rod 270. The cam groove 284 is so contoured that the upand down motion of the cam rod 270 results in the bidirectional rotationof the sector gear 288. This sector gear has straight gear teeth inconstant mesh with a series of gear teeth 292 cut longitudinally on thetransfer rod 258 over approximately half its circumference.

Accordingly, with the up and down motion of the cam rod 270, thetransfer rod 258 rotates bidirectionally about its own axis to move itsprotuberances 262, 264 and 266 between the solid line and phantompositions of FIG. 6. The transfer rod protuberances are in the solidline position, in which they are out of engagement with the grippingjaws, when the cam rod 270 is held raised under the bias of thecompression spring 282 as in FIG. 7. Upon downward travel of the cam rod270, the transfer rod protuberances 262, 264 and 266 turn to the phantomposition to engage the gripping jaws. The downward travel of the cam rod270 is effected by the following means.

As will be seen from both FIGS. 6 and 7, the bottom 140 of the jawmagazine 34 has formed therein a series of stepped bores 294 in annulararrangement about the axis of the jaw magazine. Having an upper, largerdiameter portion 296 and a lower, smaller diameter portion 298, eachbore 294 extends parallel to the axis of the jaw magazine 34. Theangular positions of these bores correspond to those of the jaw grooves150 in the jaw magazine 34. Each bore 294 receives an idler rod 300which is slidable longitudinally in its smaller diameter portion 298 andwhich is prevented from rotation by a key 302. A compression spring 304is sleeved upon each idler rod 300 and is received in the largerdiameter portion of the bore 294. This compression spring acts betweenthe magazine bottom 140 and a collar 306 on the idler rod 300 to biasthe latter upwardly. In order to limit the upward motion of the idlerrod 300, an annular abutment 308 is screwed at 310 to the magazinebottom 140 so as to close the top ends of all the stepped bores 294. Theabutment is bored at 312 to allow each idler rod 300 to slidably extendupwardly therethrough. The collar 306 on the idler rod 300 is normallyheld against the abutment 312 by the force of the compression spring304.

Each idler rod 300 has a hook 314 on its top end engageable with acomplementary hook 316 on the bottom end of the aforesaid cam rod 270.The hooks 314 and 316 are so shaped and sized in relation to each otherthat they do not interfere with each other during the rotation of thejaw magazine 34. When the jaw magazine is set out of rotation, with oneof its jaw grooves in the second jaw change position, the hook 314 ofthe idler rod 300 associated with that jaw groove engages the hook 316of the cam rod 270. Upon interengagement of the hooks 314 and 316, thecam rod 270 is constrained to joint longitudinal displacement with theidler rod 300.

Each idler rod 300 has another hook 318 on its bottom end engageablewith a complementary hook 320 on the top end of a piston rod 322 of afluid actuated, double acting, double ended rod cylinder 324. Thiscylinder has a body 326 formed in one piece with a mounting flange 328.This mounting flange is screwed at 330 to the bottom flange 146 of thehollow magazine spindle 122, so that the cylinder 324 is thereforemovable up and down with the jaw magazine 34 but is nonrotatablerelative to the carriage 92.

Just like the hooks 314 and 316, the hooks 318 and 320 are made so notto interfere with each other during the rotation of the jaw magazine 34.When the jaw magazine comes to a stop with one of its jaw grooves in thesecond jaw change position, the hook 318 of the idler rod 300 associatedwith that jaw groove comes into engagement with the hook 320 of thepiston rod 322. Upon subsequent contraction of the piston rod 322 intothe cylinder body 326, the idler rod 300 is thereby lowered against theforce of the compression spring 304 and so lowers the cam rod 270against the force of the compression spring 282. The descent of the camrod 270 results as aforesaid in the rotation of the transfer rod 258.

The cylinder 324 performs some important functions in addition to therotary actuation of the transfer rod 258. The name "multipurposecylinder" will therefore be given to this cylinder. Its additionalfunctions and further details of construction will be set forth in thecourse of the subsequent description of the jaw transfer mechanism 38and unlocking mechanism 40.

Retractable Retainer Assembly

Closely associated with the jaw transfer mechanism 36 is the retractableretainer assembly 38 seen in part in FIGS. 1, 2, 4 and 6 but bettershown in FIG. 8. The retainer assembly 38 is also wholly arranged withinthe jaw magazine 34. It includes a rotatable retainer shaft 340 disposedadjacent the second jaw change position B and extending along thetransfer rod 258 of the jaw transfer mechanism 36. The retainer shaft340 is rotatably supported by a pair of bearing members 342 and 344affixed to the hollow mounting sleeve 176 and is thereby restrained fromaxial displacement.

Three retainer pins 346, 348 and 350 are embedded in the retainer shaft340 at constant longitudinal spacings and project laterally therefrom inthe same direction. These retainer pins are movable, with thebidirectional rotation of the retainer shaft 340, into and out ofengagement with the respective gripping jaws 32' (or 32) in the secondjaw change position B through the aforesaid internal annular recesses156, 158 and 160, respectively, in the jaw magazine 34. FIG. 6 indicatesthe normal working position of the retainer pins 346, 348 and 350 by thesolid lines and their retracted position. When any set of gripping jaws32' are brought to the second jaw change position B by the rotation ofthe jaw magazine 34, the retainer pins in their solid line workingposition become engaged in the notches 162 in the jaws to prevent themfrom falling through the cutouts 170 in the jaw rests 164, 166 and 168.The retainer pins 346, 348 and 350 also function to similarly engage andtemporarily hold the gripping jaws 32 that have been transferred fromthe chuck body 30, as will be later explained in further detail.

The retainer shaft 340 has a pinion 352 rigidly mounted thereon justabove the lower bearing member 344. This pinion is in mesh with thesector gear 288 set forth in conjunction with the jaw transfer mechanism36. It will be recalled that the sector gear 288 rotates bidirectionallywith the up and down motion of the piston rod 322 of the multipurposecylinder 324. This bidirectional rotation of the sector gear 288 isimparted directly to the retainer shaft 340, besides being similarlyimparted to the transfer rod 258 of the jaw transfer mechanism 36, tocause the angular displacement of the three retainer pins 346, 348 and350 between the working and retracted positions on FIG. 6. It will beappreciated that the transfer rod 258 and retainer shaft 340 arecompelled to operate in exact synchronism with each other, being bothdriven from the same actuator via the same gear.

Unlocking mechanism

Reference is directed to FIGS. 7 and 9 in particular for the detaileddescription of the unlocking mechanism 40, although it appears also inFIGS. 1, 2 and 4. The unlocking mechanism 40 functions to unlock thegripping jaw 32 in the first jaw change position A on the chuck body 30preparatory to its transfer to the jaw magazine 34, by acting on theassociated unlocking pin 88 of the chuck 28.

The primary component of the unlocking mechanism 40 is the notedmultipurpose cylinder 324. The body 326 of this cylinder is bored at 360to provide a piston chamber slidably receiving a piston 362. An end cap364 pressure tightly closes the top end of the piston chamber 360. Thepiston 362 has the aforesaid piston rod 322 extending upwardly therefromfor selective engagement with the idler rods 300. Another piston rod 366extends downwardly from the piston 362. The axis of the piston rods 322and 366 is normal to the axis of the work spindle 26 or of the chuck 28thereon.

Mounted on the bottom end of the multipurpose cylinder piston rod 366 isa pin carrier 368 which is slidably engaged in a recess 370 in themultipurpose cylinder body 326 and which is thereby constrained to onlylinear reciprocation toward and away from the chuck 28. The undesiredrotation of the piston rod 322 is also prevented in this manner. The pincarrier 368 rigidly carries a push pin 372 extending downwardlytherefrom. When the jaw change assembly 44 is in the working position ofFIG. 2, the push pin 372 is held opposite the unlocking pin 88 of thechuck 28 associated with the gripping jaw 32 being held in the first jawchange position A.

Normally the multipurpose cylinder piston 362 is held raised as in FIGS.7 and 9. Since then the pin carrier 368 is retracted in the multipurposecylinder body recess 370, the push pin 372 allows the rotation of thechuck 28 even if the jaw change assembly 44 is in the working position.Upon descent of the piston 362, then, the push pin 372 engages andpushes the unlocking pin 88 into the associated slide 52 thereby causingthe primary detent 60, FIG. 5, of the locking mechanism 58 to move outof toothed engagement with the gripping jaw 32 being held in the firstjaw change position A.

The multipurpose cylinder 324 is further adapted to position the chuck28 so as to hold any desired jaw guideway 54 in the chuck body 30 in theexact first jaw change position with respect to the jaw guide 42 of onepiece construction with the multipurpose cylinder body 326. Toward thisend is a positioning pin 374 affixed to the pin carrier 368 in side byside relation with the push pin 372. Each slide 52 of the chuck 28 has apositioning bore 376 defined in its radially outward end for receivingthe positioning pin 374. When the jaw change assembly 44 is in theworking position, the positioning pin 374 is held opposite thepositioning bore 376 in the slide 52 associated with the gripping jaw 32being held in the first jaw change position A. Like the push pin 372 thepositioning pin 374 is held retracted in the multipurpose cylinder bodyrecess 370 when the multipurpose cylinder piston 362 is in the raisedposition, so that the positioning pin 374 does not interfere with therotation of the chuck 28. Upon descent of the piston 362 the positioningpin 374 becomes closely inserted in the associated positioning bore 376to hold the chuck 28 exactly in the required angular position withrespect to the jaw guide 42.

It will have been seen that the multipurpose cylinder 324 performs thefollowing functions in the illustrated embodiment:

1. The rotary actuation of the transfer rod 258 of the jaw transfermechanism 36.

2. The rotary actuation of the retainer shaft 340 of the retractableretainer assembly 38.

3. The unlocking of the gripping jaw 36 from the chuck body 30 in thefirst jaw change position A.

4. The positioning of the chuck body 30 relative to the jaw guide 42.

With reference directed further to FIG. 9 the pin carrier 368 has asupport 378 secured thereto. This support has a pair of switch actuators380 affixed thereto for activating limit switches, not shown, on thecylinder body 326. The unshown limit switches determine the upper andlower extremities of the multipurpose cylinder piston 362.

Jaw Guide

As will be seen from FIGS. 1, 2, 4 and 7, the jaw guide 42 is formedintegral with the multipurpose cylinder body 326. The jaw guide has apair of opposed guide walls 382 projecting forwardly (rightwardly asviewed in FIGS. 1, 2 and 7 and toward the viewer in FIG. 4) from themultipurpose cylinder body 326. The opposed guide walls 382 define incombination a guide track 384.

When the jaw change assembly 44 is in the working position as in FIG. 2,the guide track 384 serves as a substantially continuous, rectilinearpath for the gripping jaws 32 and 32' between that one of the jawguideways 54 in the chuck body 30 which is in the first jaw changeposition A and that one of the jaw grooves 150 in the jaw magazine 34which is in the second jaw change position. The guide track 384 has thesame cross sectional shape as each jaw guideway 54 in the chuck body 30and each jaw groove 150 in the jaw magazine 34 for guiding the grippingjaws 32 and 32' with a high degree of accuracy. The opposite extremitiesof the guide track may be flared for the smooth entrance of the grippingjaws therein.

It will be observed from FIG. 7 that the multipurpose cylinder body 326is slidably held against the front edge 386 of the carriage 92.Consequently, being integral with the multipurpose cylinder body 326,the jaw guide 42 is stably supported against displacement at least in adirection parallel to the work spindle 26 of the lathe 22.

OPERATION

The chuck jaw changer 20 of the above described construction operates asfollows for changing the set of gripping jaws 32 now shown mounted onthe chuck body 30 with one of the additional sets of gripping jaws 32'on the jaw magazine 34. As the unshown "director" of the N/C lathe 22puts out a jaw change command, as for a change in work to be machined,the work spindle 26 responds by decelerating and automatically comes toa stop with one of the jaw guideways 54 in the chuck body 30 orientedvertically upwardly in the first jaw change position A. Then the rotaryactuator 86 on the rear end of the headstock 24 operates to cause theforward movement of the wedge member 78 of the chuck 28. The result isthe radially outward movement of the three gripping jaws 32 on the chuckbody 30.

It is assumed that the jaw change assembly 44 has so far been held inthe retracted position of FIG. 1. Now the jaw change assembly must bemoved to the working position of FIG. 2. Toward this end thelongitudinal cylinder 96 of the longitudinal transport mechanism 46 isfirst extended to move the carriage 92 to the front position togetherwith the jaw change assembly 44 thereon. Then the radial cylinder 116 ofthe radial transport mechanism 48 is contracted to lower the jaw changeassembly 44 as in FIG. 2. With the jaw change assembly thus placed inthe working position, an empty jaw groove 150 in the jaw magazine 34lies in the second jaw change position B. The jaw guide 42 is alsopositioned with its guide track 384 in line with the jaw guideway 54 inthe first jaw change position A and with the jaw groove 150 in thesecond jaw change position B.

The jaw magazine 34 has the additional sets of gripping jaws 32' mountedin all but one of the fifteen jaw grooves 150 by making use of theretractable bridges 186, FIG. 6, in the discontinuities of the jaw rests164, 166 and 168. The jaw magazine 34 may be indexed by the indexingmechanism 35 to bring the one empty jaw groove to the second jaw changeposition B, either before or after the jaw change assembly 44 is movedto the working position as above. Generally, however, the jaw groove 150from which the set of gripping jaws has previously been transferred tothe chuck body 30 may be held in the second jaw change position toaccept the same jaw set.

Then the transfer cylinder 240 of the jaw transfer mechanism 36 isactivated to lower the cylinder body 250 a distance equal to the pitch Pof the gripping jaws 32 and 32' aligned in the first and second jawchange positions A and B. FIG. 10 shows the transfer cylinder body 250thus lowered. Rigidly coupled to this transfer cylinder body, thetransfer rod 258 descends therewith the same distance. The threeprotuberances 262, 264 and 266 on the transfer rod 258 are also arrangedwith the pitch P, so that the lowermost protuberance 266 is now on thesame level with the notch 162 in the gripping jaw 32 being held in thefirst jaw change position A on the chuck body 30. The other twoprotuberances 262 and 264 are on the same levels with the middle andlowermost retainer pins 348 and 350, respectively, on the retainer shaft340 of the retractable retainer assembly 38. The multipurpose cylinder324 has still its piston 362 held raised, so that the protuberances 262,264 and 266 on the transfer rod 258 are in the solid line position ofFIG. 6, with the lowermost protuberances 266 out of engagement with thegripping jaw 32 in the first jaw change position A.

Then the multipurpose cylinder 324 has its piston 362 lowered as in FIG.11 to perform the above enumerated four functions. First of all, upondescent of the multipurpose cylinder piston 362, the push pin 372 on thepin carrier 368 on its lower piston rod 366 engages and pushes thatunlocking member 88 of the chuck 28 which is associated with thegripping jaw 32 being held in the first jaw change position A. Thepushing of the unlocking member 88 results in the retraction of theprimary detent 60 of the associated locking mechanism 58 against theforce of the compression springs 74, out of positive engagement with thegripping jaw 32 in the first jaw change position A. This gripping jaw isnow free to be withdrawn from the chuck body 30. However, the secondarydetent 66 of the locking mechanism 58 is still engaged with the grippingjaw 32 under the bias of the compression spring 76, preventing the jawfrom slipping down the jaw guideway 54. The secondary detent 66 yieldsas aforesaid when the gripping jaw 32 is subsequently forced upwardly bythe jaw transfer mechanism 36.

Also, upon descent of the multipurpose cylinder piston 362, thepositioning pin 374 on the pin carrier 368 becomes engaged in thepositioning hole 376 in that slide 52 of the chuck 28 which isassociated with the gripping jaw 32 being held in the first jaw changeposition A. The position pin 374 thus positions the slide 52, andtherefore the chuck body 30, with respect to the jaw guide 42 integralwith the multipurpose cylinder body 326. That jaw guideway 54 in thechuck body 30 which is in the first jaw change position A is now exactlyin line with the guide track 384 defined by the jaw guide 42.

The descent of the multipurpose cylinder piston 362 results further inthe rotary activation of the jaw transfer mechanism 36 and retractableretainer assembly 38. The upper piston rod 322 of the multipurposecylinder 324 has been hooked onto that one of the idler rods 300 on thejaw magazine bottom 140 which is associated with the empty jaw groove150 now in the second jaw change position B. This idler rod 300 has beenfurther hooked onto the cam rod 270. Consequently, upon descent of themultipurpose cylinder piston 362, the idler rod 300 lowers against theforce of the compression spring 304, lowering in turn the cam rod 270against the force of the compression spring 282. This descent of the camrod 270 results in the rotation of the sector gear 288 in a clockwisedirection, as viewed in FIG. 6, via the cam follower pin 290 slidablyengaged in the cam groove 284 in the cam rod. Directly in mesh with thesector gear 288, the transfer rod 258 of the jaw transfer mechanism 36rotates counterclockwise, as seen also in FIG. 6, with the result thatthe three protuberances 262, 264 and 266 on the transfer rod move fromthe solid line retracted position of FIG. 6 to the phantom workingposition. The transfer rod 258 has been lowered. With itscounterclockwise rotation, therefore, the lowermost protuberance 266thereon moves into engagement in the notch 162 in the gripping jaw 32 inthe first jaw change position A, as illustrated in FIG. 11. The othertwo protuberances 262 and 264 on the transfer rod 258 serve no usefulpurpose at this time as there is no gripping jaw in the second jawchange position B.

Also in mesh with the sector gear 288 via the pinion 352 thereon, theretainer shaft 340 of the retractable retainer assembly 38 likewiserotates counterclockwise, as viewed in FIG. 6, upon clockwise rotationof the sector gear. Thereupon the three retainer pins 346, 348 and 350turn from the solid line working position of FIG. 6 to the phantomretracted position and so retract away from the jaw groove 150 in thesecond jaw change position B.

The gripping jaw 32 in the first jaw change position A is now ready fortransfer from chuck body 30 to jaw magazine 34. The transfer cylinder240 is reactivated to cause the ascent of its body 250 back to itsinitial position of FIGS. 1 and 2 together with the transfer rod 258coupled thereto. FIG. 12 shows the transfer rod 258 thus raised with thegripping jaw 32 in engagement with the lowermost protuberance 266thereon. Withdrawn from the jaw guideway 54 in the chuck body 30 by theascending transfer rod 258, the gripping jaw will smoothly enter theguide track 384 defined by the jaw guide 42 and will thereby beaccurately directed into the empty jaw groove 150 in the jaw magazine 34in the second jaw change position B. The gripping jaw 32 will stop withits notch 162 on a level with the lowermost retainer pin 350 on theretainer shaft 340 now held retracted. This lowermost retainer pin is toengage and hold the gripping jaw 32 upon subsequent retraction of thelowermost protuberance 266 out of engagement in its notch 162.

Then the multipurpose cylinder piston 362 is raised as in FIG. 13.Thereupon the push pin 372 on the multipurpose cylinder piston rod 366releases the unlocking member 88, thereby allowing the associatedprimary detent 60, and therefore the unlocking member itself, to springback to their normal positions. The positioning pin 374 on themultipurpose cylinder piston rod 366 also withdraws out of thepositioning hole 376 in the chuck slide 52.

Further, with the ascent of the multipurpose cylinder piston 362, itspiston rod 322 raises the cam rod 270 back to its initial position viaone of the idler rods 300. The ascending cam rod 270 turns the sectorgear 288 in a clockwise direction, as viewed in FIG. 6, via the camfollower pin 290 slidably engaged in the cam groove 284. The result isthe clockwise rotation of both transfer rod 258 and retainer shaft 340.With the clockwise rotation of the transfer rod 258, the threeprotuberances 262, 264 and 266 thereon all move away from the jaw groove150 in the second jaw change position B. Thus the lowermost protuberance266 moves out of engagement in the notch 162 in the gripping jaw 32.This gripping jaw does not fall from the jaw magazine 34, however, asthe retainer shaft 340 revolves clockwise at the same time with thetransfer rod 258. Just before the lowermost protuberance 266 on thetransfer rod leaves the gripping jaw notch 162, the lowermost retainerpin 350 on the retainer shaft 340 becomes engaged therein. The lowermostretainer pin holds the gripping jaw on the jaw magazine 34 after thelowermost protuberance 266 has disengaged the same, as illustrated inFIG. 13.

Then the work spindle 26 of the N/C lathe 22 is automatically turnedthrough a preassigned angle to bring the second gripping jaw on thechuck body 30 to the first jaw change position A.

Then the transfer cylinder body 250 is lowered again together with thetransfer rod 258 coupled thereto until the lowermost protuberance 266thereon reaches the position on a level with the notch 162 in the secondgripping jaw 32, as has been set forth with reference to FIG. 10 inconnection with the first gripping jaw that has been transferred asabove to the jaw magazine 34. The middle protuberance 264 on thetransfer rod 258 is now on a level with the first gripping jaw 32 beingheld by the lowermost retainer pin 350 in the jaw groove 150 in the jawmagazine 34.

Then the multipurpose cylinder piston 362 is lowered again. As has beendescribed with reference to FIG. 11 the descent of the multipurposecylinder piston 362 results in the unlocking of the second gripping jaw32 from the primary detent 60 of the associated locking mechanism 58,and in the positioning of the chuck body 30 with respect to the jawguide 42. Further the transfer rod 258 and retainer shaft 340 are bothrevolved counterclockwise as viewed in FIG. 6. Thereupon the lowermostprotuberance 266 on the transfer rod 258 becomes engaged in the notch162 in the second gripping jaw 32 on the chuck body 30, whereas themiddle protuberance 264 thereon becomes engaged in the notch 162 in thefirst gripping jaw 32 being held in the lowermost position on the jawmagazine 34 as the lowermost retainer pin 350 on the retainer shaft 340moves out of engagement with the first gripping jaw.

Then the transfer cylinder 240 is reactivated to cause the ascent of itsbody 250 together with the transfer rod 258. Having its lower twoprotuberances 264 and 266 engaged with the first and second grippingjaws 32, the transfer rod 258 moves the second jaw from the chuck body30 to the lowermost position on the jaw magazine 34, and the first jawfrom the lowermost to the middle position on the jaw magazine.

The third gripping jaw 32 can likewise be transferred from chuck body 30to jaw magazine 34. The complete set of gripping jaws thus transferredonto the jaw magazine 34 are aligned in the jaw groove 150 in the secondposition B just like all the other sets of gripping jaws 32' in theother jaw grooves in the jaw magazine.

Following the transfer of the final gripping jaw 32 from chuck body 30to jaw magazine 34 by the transfer rod 258, the multipurpose cylinderpiston 362 is raised to cause the push pin 52 to release the unlockingmember 88, and to cause withdrawal of the positioning pin 374 from thepositioning hole 376. Further the transfer rod protuberances 262, 264and 266 are moved out of engagement with the three gripping jaws 32 thathave been transferred to the jaw magazine 34; instead, the retainer pins346, 348 and 350 are moved into engagement with the gripping jaws forholding them in position on the jaw magazine until the latter is setinto rotation by the magazine indexing mechanism 35.

Next comes the step of transferring a desired new set of gripping jaws32' from jaw magazine 34 to chuck body 30. The desired set of grippingjaws must first be moved to the second jaw change position B. Themagazine indexing mechanism 35 is set into operation to revolve the jawmagazine 34 about the hollow magazine spindle 122. During such rotationof the jaw magazine 34 the jaw identifying switch assembly 232 sensesthe approach to the second jaw change position B of that jaw groove 150which has the desired set of gripping jaws engaged therein. Then, as theproximity switch 228 senses the arrival of that jaw groove at the secondjaw change position B from the associated idler rod 300, the indexingmotor 210 is automatically set out of rotation. Now the desired set ofgripping jaws 32' are set in the second jaw change position B by beingsupported by the respective retainer pins 346, 348 and 350 on theretainer shaft 340.

As the jaw magazine 34 starts rotation as above, the old set of grippingjaws 36 that have been held in the second jaw change position B rideonto the jaw rests 164, 166 and 168 from the retainer pins 346, 348 and350, respectively. These retainer pins remain in the working position ofFIG. 6 throughout the rotation of the jaw magazine 34.

Then the multipurpose cylinder piston 362 is lowered (see FIG. 11) forthe following four purposes:

1. The pushing of the unlocking member 88 into the chuck slide 52, withthe consequent retraction of the primary detent 60 of the lockingmechanism 58 against the forces of the compression springs 74 so as notto interfere with the first new gripping jaw 32' to be subsequentlytransferred from the jaw magazine 34.

2. The positioning of the chuck body 30 with respect to the jaw guide42.

3. The retraction of the retainer pins 346, 348 and 350 on the retainershaft 340 out of engagement with the new set of gripping jaws 32' in thejaw groove 150 in the second jaw change position B.

4. The engagement of the new set of gripping jaws 32' by theprotuberances 262, 264 and 266 on the transfer rod 258.

Then the transfer cylinder body 250 is lowered (see FIG. 10) to causethe descent of the transfer rod 258 the required distance P. Thetransfer rod 258 transfers the lowermost one of the new set of grippingjaws 32' into that jaw guideway 54 in the chuck body 30 which is beingheld in the first jaw change position A. Further the transfer rod 258carries the uppermost gripping jaw to the middle position on the jawmagazine 34, and the intermediate gripping jaw to the lowermost positionthereon.

Then the multipurpose cylinder piston 362 is raised for the followingpurposes:

1. The locking of the first new gripping jaw 32' by the primary detent60 of the associated locking mechanism 58.

2. The withdrawal of the positioning pin 374 from the positioning hole376 in the chuck slide 52.

3. The disengagement of the protuberances 262, 264 and 266 on thetransfer rod 258 from the new set of gripping jaws 32'.

4. The engagement of the upper two new gripping jaws 32', lying in themiddle and lowermost positions on the jaw magazine 34 as above, by thelower two retainer pins 348 and 350 on the retainer shaft 340.

The locking of the first new gripping jaw 32' on the chuck body 30 takesplace as the primary detent 60 is sprung into toothed engagementtherewith upon release of the unlocking member 88 by the push pin 372 onthe multipurpose cylinder piston rod 366.

Then the transfer cylinder 240 operates to return the unloaded transferrod 258 into the jaw magazine 34. Then the work spindle 26 of the N/Clathe 22 is turned an angle required to bring the next jaw guideway 54in the chuck body 30, from which the gripping jaw 32 was withdrawn forthe second time, to the first jaw change position A.

Thereafter the foregoing cycle of operation is repeated to transfer thesecond, and then the third, gripping jaws from jaw magazine 34 to chuckbody 30.

Then the radial cylinder 116 of the radial transport mechanism 48operates to raise the complete jaw change assembly 44 away from thechuck 28. Then the longitudinal cylinder 96 of the longitudinaltransport mechanism operates to return the jaw change assembly 44 to theretracted position of FIG. 1 together with the carriage 92. A changefrom one set of gripping jaws 32 to another 32' has now been completed.

Possible Modifications

The preferred form of the chuck jaw changer disclosed in the foregoingis by way of example only and is not intended to impose limitations uponthe invention. A variety of modifications or variations of the disclosedembodiment will readily occur to one skilled in the art withoutdeparting from the spirit or scope of the invention as expressed in theclaims appended hereto. The following is a brief list of such possiblemodifications:

1. Each gripping jaw on the chuck body may be locked against radialdisplacement by the associated slide, instead of by the spring loadeddetent, with the slide made movable into and out of positive engagementwith the jaw as by a fluid actuated cylinder mounted on the rear end ofthe work spindle.

2. All the gripping jaws of the chuck may be simultaneously locked andunlocked with respect to the chuck body.

3. The gripping jaws may be locked and unlocked by pivotable means,instead of by the linearly movable members.

4. The jaw magazine may not be in the form of a rotary cylinder or drumbut may take the form of a flat plate movable linearly, with a requirednumber of jaw grooves defined therein side by side.

5. The jaw guide may be omitted, although its provision is preferredbecause it can accurately guide the gripping jaws into the jaw guidewaysin the chuck body and into the jaw grooves in the jaw magazine even if asubstantial spacing exists between chuck body and jaw magazine.

What is claimed is:
 1. A chuck jaw changer for use with a machine tool(22) having a work spindle (26), said jaw changer operable with aplurality of interchangeable sets of gripping jaws (32, 32'),comprising:(a) a chuck (28) having a chuck body (30) adapted to bemounted on the work spindle (26) of the machine tool, the chuck bodyhaving a plurality of jaw guideways (54) arranged radially of the workspindle for replaceably receiving a set of slidable gripping jaws (32)for chucking and unchucking work, each gripping jaw being slid into andout of one of the jaw guideways in a radial direction of the workspindle when that jaw guideway is in a preassigned first jaw changeposition on the work spindle; (b) a jaw magazine (34) in the form of ahollow cylinder adapted to be mounted on the machine tool and beingrotatable relative thereto about an axis oriented radially of the workspindle of the machine tool, said jaw magazine having a plurality of jawgrooves (150) at circumferential spacings in said hollow cylinder, eachjaw groove adapted to receive an additional set of gripping jaws (32')or the first recited set of gripping jaws (32), as the latter arewithdrawn from the chuck body, said gripping jaws releasably engaged insaid grooves and in alignment; (c) an indexing mechanism (35) disposedinternally of said cylindrical jaw magazine (34) for moving the jawmagazine relative to the machine tool so as to bring any one of the jawgrooves, with or without a set of gripping jaws engaged therein, to apreassigned second jaw change position where the jaw groove is in linewith that one of the jaw guideways in the chuck body which is in thefirst jaw change position, the aligned gripping jaws in the first jawchange position and in the second jaw change position being held atconstant pitch distances; and (d) a jaw transfer mechanism (36) disposedinternally of said cylindrical jaw magazine (34) and movable between thechuck and the jaw magazine a distance equal to the pitch distancebetween the gripping jaws aligned in the first and second jaw changepositions, the jaw transfer mechanism being capable of simultaneouslyengaging the set of gripping jaws being held in the jaw groove in thesecond jaw change position for transferring the same into the successivejaw guideways being held in the first jaw change position, the jawtransfer mechanism being further capable of engaging the gripping jawbeing held in the jaw guideway in the first jaw change position fortransferring the same into the jaw groove in the second jaw changeposition; (e) whereby each complete set of gripping jaws can betransferred from the chuck body to the jaw magazine, or vice versa,while the jaw magazine is standing still on the machine tool with one ofthe jaw grooves held in the second jaw change position.
 2. The chuck jawchanger of claim 1 further comprising a jaw guide (42) for providing asubstantially continuous, rectilinear guide track (384) between that oneof the jaw guideways (54) in the chuck body (30) which is in the firstjaw change position and that one of the jaw grooves (150) in the jawmagazine (34) which is in the second jaw change position, for the smoothtransfer of the gripping jaws (32, 32') therebetween by the jaw transfermechanism (36).
 3. The chuck jaw changer of claim 2 further comprising alongitudinal transport mechanism (46) for jointly moving the jawmagazine (34) and the indexing mechanism (35) and the jaw transfermechanism (36) in the longitudinal direction of the work spindle (26) ofthe machine tool (22) relative to the same between a first retractedposition away from the chuck (28) and a second working position closerto the chuck.
 4. The chuck jaw changer of claim 3 wherein thelongitudinal transport mechanism (46) comprises:(a) a carriage (92)movable on the machine tool (22) between said retracted first and secondworking positions, the carriage having the jaw magazine (34) rotatablymounted thereon and having the indexing mechanism (35) and jaw transfermechanism (36) nonrotatably mounted thereon; and (b) means (96) on themachine tool for moving the carriage between said retracted first andsecond working positions.
 5. The chuck jaw changer of claim 4 furthercomprising a radial transport mechanism (48) on the carriage (92) of thelongitudinal transport mechanism (46) for jointly moving the jawmagazine (34), the indexing mechanism (35), the jaw transfer mechanism(36) and the jaw guide (42) in a radial direction of the work spindle(26) of the machine tool (22) relative to the carriage, the radialtransport mechanism moving the jaw magazine and the indexing mechanismand the jaw transfer mechanism toward the chuck (28) for jaw change andaway from the chuck upon completion of the jaw change when the carriageis in the second working position.
 6. The chuck jaw changer of claim 5wherein the jaw magazine (34) is in the form of a hollow cylinder havingthe jaw grooves (150) defined at circumferential spacings therein, andwherein the radial transport mechanism (48) comprises:(a) a column (112)rigidly mounted on the carriage (92) of the longitudinal transportmechanism (46) and extending in a radial direction of the work spindle(26) of the machine tool (22); (b) a hollow magazine spindle (122)slidably fitted over the column and constrained to only axialdisplacement relative to the same; and (c) means (116) for reciprocablymoving the magazine spindle axially relative to the column; (d) themagazine spindle having the jaw magazine concentrically and rotatablymounted thereto and having the indexing mechanism (35) and the jawtransfer mechanism (36) nonrotatably mounted thereon.
 7. The chuck jawchanger of claim 1 wherein the chuck further comprises:(a) a pluralityof slides (52) slidably engaged respectively in another set of radialguide ways (50) defined in the chuck body (30) and disposed opposite therespective gripping jaws (32) engaged in the jaw guideways (54) in thechuck body; (b) a locking mechanism (58) for locking each gripping jawagainst displacement relative to the opposed one of the slides; and (c)means (86) acting on the slides for moving the gripping jaws radially ofthe chuck body.
 8. The chuck jaw changer of claim 7 further comprisingan unlocking mechanism (40) operatively associated with the jaw transfermechanism (36) for causing one of the locking mechanisms (58) to unlockthe gripping jaw (32) engaged in that one of the jaw guideways (54) inthe chuck body (30) which is held in the first jaw change position,preparatory to the transfer of the gripping jaw from the chuck body tothe jaw magazine (34).
 9. The chuck jaw changer of claim 1 wherein thejaw magazine (34) is disposed upstandingly on the machine tool (22) andis provided with a plurality of annular jaw rests (164, 166, 168)arranged concentrically therewith and at vertical spacings with respectto one another for holding thereon the gripping jaws (32') received inthe jaw grooves (150) in the jaw magazine.
 10. The chuck jaw changer ofclaim 9 wherein each jaw rest (164, 166, 168) is nonrotatable relativeto the machine tool (22) and is partly cut off (170) in the second jawchange position of the jaw grooves (150) for the passage of the grippingjaws (32, 32') being transferred between the chuck body (30) and the jawmagazine (34).
 11. The chuck jaw changer of claim 10 wherein the topedge (182) of the lowermost one (168) of the jaw rests (164 166, 168),slidably holding the gripping jaws (32') thereon, slope downwardly as itextends toward the opposite extremities of the jaw rest bounding thepart where it is cut off.
 12. The chuck jaw changer of claim 1 whereinsaid jaw transfer mechanism (36) comprises an elongated member (258)extending along a jaw groove (150) in the jaw magazine which is in thesecond jaw change position, said elongated member having means (262,264, 266) within the jaw magazine engageable with at least one of saidgripping jaws (32') being held in a jaw groove which is in the secondjaw change position.
 13. A chuck jaw changer for use with a machine tool(22) having a work spindle (26), said jaw changer operable with aplurality of interchangeable sets of gripping jaws (32, 32'),comprising:(a) a chuck (28) having a chuck body (30) adapted to bemounted on the work spindle (26) of the machine tool, the chuck bodyhaving a plurality of jaw guideways (54) arranged radially of the workspindle for replaceably receiving a set of slidable gripping jaws (32)for chucking and unchucking work, each gripping jaw being slide into andout of one of the jaw guideways in a radial direction of the workspindle when that jaw guideway is in a preassigned first jaw changeposition on the work spindle; (b) a jaw magazine (34) adapted to beoperatively mounted on the machine tool and having a plurality of jawgrooves (150) therein, each jaw groove adapted to receive an additionalset of gripping jaws (32'), or the first recited set of gripping jaws(32), as the latter are withdrawn from the chuck body, said grippingjaws releasably engaged in said grooves and in alignment; (c) anindexing mechanism (35) for moving the jaw magazine relative to themachine tool so as to bring any one of the jaw grooves, with or withouta set of gripping jaws engaged therein, to a preassigned second jawchange position where the jaw groove is in line with that one of the jawguideways in the chuck body which is in the first jaw change position,the aligned gripping jaws in the first jaw change position and in thesecond jaw change position being held at constant pitch distances; and(d) a jaw transfer mechanism (36) movable between the chuck and the jawmagazine a distance equal to the pitch distance between the grippingjaws aligned in the first and second jaw change positions, the jawtransfer mechanism being capable of simultaneously engaging the set ofgripping jaws being held in the jaw groove in the second jaw changeposition for transferring the same into the successive jaw guidewaysbeing held in the first jaw change position, the jaw transfer mechanismbeing further capable of engaging the gripping jaw being held in the jawguideway in the first jaw change position for transferring the same intothe jaw groove in the second jaw change position, said jaw transfermechanism (36) comprising a transfer rod (258) extending along that oneof the jaw grooves (150) in the jaw magazine (34) which is in the secondjaw change position, said transfer rod supported within said jawmagazine both for rotation about its own axis and for longitudinalmovement between the jaw magazine and the chuck body (30), and aplurality of protuberances (262, 264, 266) on the transfer rod movable,with the rotation of the transfer rod, into and out of engagement withthe set of gripping jaws (32') being held in that one of the jaw groovesin the jaw magazine which is in the second jaw change position, one ofthe protuberances being further movable into and out of engagement withthe gripping jaw (32) being held in that one of the jaw guidewys (54) inthe chuck body which is in the first jaw change position; (e) wherebyeach complete set of gripping jaws can be transferred from the chuckbody to the jaw magazine, or vice versa, while the jaw magazine isstanding still on the machine tool with one of the jaw grooves held inthe second jaw change position.
 14. The chuck jaw changer of claim 13further comprising a retractable retainer assembly (38) for retainingthe gripping jaws (32, 32') in that one of the jaw grooves (150) in thejaw magazine (34) which is in the second jaw change position, when theprotuberances (262, 264, 265) on the transfer rod (258) of the jawtransfer mechanism (36) are moved out of engagement with the grippingjaws.
 15. The chuck jaw changer of claim 14 wherein the retractableretainer assembly (38) comprises:(a) a rotatable retainer shaft (340)extending along the transfer rod (258) of the jaw transfer mechanism(36); and (b) a plurality of retainers (346, 348, 350) projectinglaterally from the retainer shaft for movement into and out ofengagement with the gripping jaws 32, 32') with the rotation of theretainer shaft.
 16. The chuck jaw changer of claim 15 wherein the chuck(28) is further provided with a locking mechanism (58) for locking eachgripping jaw (32) against displacement relative to the chuck body (30),and wherein the chuck jaw changer further comprises:(a) a fluidactuated, double ended rod cylinder (324) having first and second pistonrods (366, 322), the first piston rod acting on the locking mechanism tocause the same to unlock the gripping jaw engaged in that one of the jawguideways (54) in the chuck body which is held in the first jaw changeposition, preparatory to the transfer of the gripping jaw from the chuckbody to the jaw magazine (34); (b) cam means (272, 290) for translatingthe linear reciprocation of the second piston rod (322) of the cylinderinto bidirectional rotation; and (c) gear means (288, 292, 352) forimparting the bidirectional rotation of the cam means to the transferrod (258) of the jaw transfer mechanism (36) and to the retainer shaft(340) of the retractable retainer assembly (38).
 17. The chuck jawchanger of claim 16 further comprising a jaw guide (42) formed in afixed relation with the double ended rod cylinder (324) for providing asubstantially continuous, rectilinear guide track between that one ofthe jaw guideways (54) in the chuck body (30) which is in the first jawchange position and that one of the jaw grooves (150) in the jawmagazine (34) which is in the second jaw change position, for the smoothtransfer of the gripping jaws (32, 32') therebetween.
 18. The chuck jawchanger of claim 17 wherein the first piston rod (366) of the doubleended rod cylinder (324) is further adapted to hold any of the jawguideways (54) in the chuck body (30) in the exact first jaw changeposition by locking the chuck body against displacement relative to thejaw guide (42) during jaw transfer.
 19. A chuck jaw changer for use witha machine tool (22) having a work spindle (26), said jaw changeroperable with a plurality of interchangeable sets of gripping jaws (32,32'), comprising:(a) a chuck (28) having a chuck (30) adapted to bemounted on the work spindle (26) of the machine tool, the chuck bodyhaving a first set of jaw guideways (54) arranged radially of the workspindle for replaceably receiving a set of slidable gripping jaws (32)for chucking and unchucking work, each gripping jaw being slid into andout of one of the jaw guideways in a radial direction of the workspindle when that jaw guideway is in a preassigned first jaw changeposition on the work spindle, said chuck (28) further comprising aplurality of slides (52) slidably engaged respectively in a second setof radial guideways (50) positioned in the chuck body (30) and disposedopposite the respective gripping jaws (32) slidably engaged in the jawguideways (54) in the chuck body, a locking mechanism (58) for lockingeach gripping jaw against displacement relative to the opposed one ofthe slide, means (86) acting on the slides for moving the gripping jawsradially of the chuck body, and an unlocking member (88) to be activatedfor causing each locking mechanism (58) to unlock the correspondinggripping jaw (32); (b) a jaw magazine (34) adapted to be operativelymounted on the machine tool and having a plurality of jaw grooves (150)therein, each jaw groove adapted to receive an additional set ofgripping jaws (32') or the first recited set of gripping jaws (32), asthe latter are withdrawn from the chuck body, said gripping jawsreleasably engaged in said grooves and in alignment; (c) an indexingmechanism (35) for moving the jaw magazine relative to the machine toolso as to bring any one of the jaw grooves, with or without a set ofgripping jaws engaged therein, to a preassigned second jaw changeposition where the jaw groove is in line with that one of the jawguideways in the chuck body which is in the first jaw change position,the aligned gripping jaws in the first jaw change position and in thesecond jaw change position being held at constant pitch distances; (d) ajaw transfer mechanism (36) movable between the chuck and the jawmagazine a distance equal to the pitch distance between the grippingjaws aligned in the first and second jaw change positions, the jawtransfer mechanism being capable of simultaneously engaging the set ofgripping jaws being held in the jaw groove in the second jaw changeposition for transferring the same into the successive jaw guidewaysbeing held in the first jaw change position, the jaw transfer mechanismbeing further capable of engaging the gripping jaw being held in the jawguideway in the first jaw change position for transferring the same intothe jaw groove in the second jaw change position; (e) a jaw guide (42)for providing a substantially continuous, rectilinear guide track (384)between that one of the jaw guideways (54) in the chuck body (30) whichis in the first jaw change position and that one of the jaw grooves(150) in the jaw magazine (34) which is in the second jaw changeposition, for the smooth transfer of the gripping jaws therebetween bythe jaw transfer mechansim (36); (f) a fluid actuated cylinder (324)formed substantially integral with the jaw guide, said fluid actuatedcylinder having a piston rod (366) thereon; (g) a push pin (372) on thepiston rod (366) of the fluid actuated cylinder for activating eachunlocking member (88) of the chuck; and (h) a positioning pin (374) onthe piston rod of the fluid actuated cylinder, a bore (376) in eachslide (52) of the chuck, said positioning pin (374) engageable with saidbore (376) for holding any of the jaw guideways (54) in the chuck bodyin the exact first jaw change position with respect to said jaw guide;(i) whereby each complete set of gripping jaws can be transferred fromthe chuck body to the jaw magazine, or vice versa, while the jawmagazine is standing still on the machine tool with one of the jawgrooves held in the second jaw change position.